Workshops/mini games jam

https://wiki.london.hackspace.org.uk/view/Workshops/mini_games_jam ultra-quick game making tools:

http://www.lexaloffle.com/pico-8.php

http://www.renpy.org

http://twinery.org

http://www.puzzlescript.net

http://www.flickgame.org

(please add more (but only if you've used them personally) !)